Elmer 33 - 1 and 1 plus

[ShopShoe]

Back in April I first thought about building Elmer Verburg's No. 33 Mill Engine at 150 percent size, so that it would be a little larger with about a 4.5-inch. flywheel. Once that decision was made, I sat down with the drawings from john-tom.com and starting planning. I had forgotten that Elmer liked fractional inches.

A few days later I ended up deciding that I might as well go through Elmer's drawings for and change the measurements to decimals, then figure out the sizes for the one-and-a-half sized version. I needed to determine what materials to order as well.

I digress a little here to explain that I used to have a techie job where I prepared proposals for installations, interpreting someone's needs to plans and specs, and ultimately to purchase orders and contracts. So it looks like a spreadsheet will get made and I'll decide how to name documents and everything.

So, I have also made the decision to show a lot of this stuff in the log as some of the newcomers to the hobby may find it useful. It is also going to be important for me to be organized as I expect to take a while to get this project done: I expect that I will be diverted by family caretaking, home improvements, and some other shop projects and tooling builds. I am afraid that there will be some of that "excrutiating minutiae" in this thread.

I have considered a parallel thread which summarizes and highlights the progress, perhaps in another place. This would be for those who may want to know how this progress is going, but without so many updates.

The first step is the spreadsheet I made to get an idea of materials. The second page looks like this:

I took this out to my shop and determined what I had in stock and what would need to be ordered. I also made two other decisions at this stage. I will buy flywheel castings, because I think they will look "right" on this engine and I already have enough parts to make. I don't know how it will go with castings, but I can also change my mind if I want. I also decided that I will use unstudly studs made from threaded rod, instead of screws or bolts. Adding some tools and miscellaneous items to the fastener hardware and metal stock needed for this project, and some others, resulted in orders out to three places. I will probably also have to get some more cutters before I am done, but that can wait.

--ShopShoe

 

[kjk]

You may already be aware of Jon Somers versions of this engine. He built it at planned dimensions and at 150%.

You can see photos of the finished engines here:

http://start-model-engineering.co.uk/my-engines/

 

[ShopShoe]

kjk,

Thank you. I was not aware of that pair of engines. I was aware of the site, but have not visited it.

--ShopShoe

 

[ShopShoe]

Now I spend a lot of time at the computer, as I have also decided to draw a lot of the parts in CAD as I struggle with the measurements. I am using a 2D/3D CAD program, but I am not fully modeling the engine. I am making drawings as shop notes: I tend to make my own "Crap-O-CAD" in actual CAD, putting in dimensions and using 2D and 3D and selected views to help me see what I need in the shop. These drawings are not following any specific conventions or standards, they are not what I would provide for someone else to follow. I do not plan to provide these because I do not think I can because of copyright, but I may show pieces of them as illustrations as I go.

The first step was really to go through Elmer's drawing and assign a number to each part, then the spreadsheet was developed to find or purchase materials. The next thing I will do is draw each part. For those who are interested, I have determined to name each drawing using this scheme:

--

Elmer_33_ [1 for 100%]_ (Part [No] ["B", etc. if alternate view]_v[version]n)
[15 for 150%]_


One drawing for each part first

Folder for each size version, with relevant drawings inside.

X to indicate experimental or trial drawing

ASSY to indicate 3-D model of trial assembly

--ShopShoe

 

[ShopShoe]

I need to explain that I have read others' build logs for this engine, but I have decided to make my version primarily as I interpret and redraw the plans. I will try to solve as many problems in my own way, but one cannot help but be influenced by what others have done: So I will occasionally look at the previous builds when I feel an issue was raised before.

After several sessions of drawing, I worked my through 10 parts, starting with the Floor and ending at the Valve. At this point I come to the CrossHead Guides, where Sshire debated the size of nuts used and ended up using 4-40 scale nuts. He had also discussed making the crosshead guides larger to even things up a bit.

This is where 3-D modeling helps a little bit.

The part as drawn by Elmer and redrawn by me, with the 3-48 hardware and the "small pattern" 3-48 nuts as sold by McMaster-Carr. Also the part drawn wider with the same nuts, and with different orientations of the nut.

So, If I actually made the crosshead guides wider, then I would have to change the mounting locations on the base, possible modify the base, and modify the crosshead.

On the 150 per cent version, the wider crosshead guides would come out like this, with the 6-32 hardware I would use.

At this point I put things aside for a few days and started contemplating the special hardware. Late at night I start wondering if it would be hard to make hardware, but I don't want to get involved in a side project like this. Perhaps I could just drill and tap smaller nuts to come up with something. Back to the CAD program with the dimensions of the 2-56 and 4-40 nuts I do have to see what they would look like.

I decided that this idea actually needs to be tried in the shop and here is the result. A 2-56 nut on a 3-48 thread on a piece of scrap the width of the part as Elmer spec'd it.

I think I'll go with this. I know this is nonstandard hardware, but this is a concept engine that is not being modeled from a real engine in true scale.

--ShopShoe

 

[ShopShoe]

It looks like I will be using the dimensions from Elmer on the 100 per cent version, with the corresponding up-sizing for the 150 per cent version. I think I will vary from straight scaling of the two versions at this point, and make the 100 per cent version Crosshead Guides in the "plain" design from Elmer, but try the alternate version for the larger model. This is the version with the five holes along the sides: Perhaps it looks more "industrial."

--ShopShoe

 

[ShopShoe]

Static Update

Just so I stay on this project I need to report that I'm still CAD drawing parts plans for these engines while working on a minor tool build/enhancement out in the shop. If that works out I may do an after-the-fact build log. Meanwhile, people in my family not feeling well, washing machine throwing a bearing, oven T-stat off calibration, and bad weather marching across Midwest USA.

I hope to actually start cutting metal on the two 33s soon.

--ShopShoe